chore(server/transporter): set RequestTimout reasonable
chore(config): reset retry interval

Make retry interval random one to avoid join collision.
chore(etcd): loose request timeout

This is a hack to improve multi-etcd boot process.
It could make users alwasy start etcd cluster successfully.
chore(server/transporter): remove unnecessary timeout
Merge pull request #624 from unihorn/36

chore(server/transporter): set RequestTimout reasonable